Advancements in communication technologies have permitted the development, implementation, and popular utilization of new types of communication systems. Such advancements are also implemented in existing communication systems to improve operational characteristics thereof. When implemented in communication systems, the advancements in communication technologies generally permit communications to be effectuated at increased rates of data transmission and otherwise provide for improved qualities and quantities of communication data transfer between sending and receiving stations operable in such communication systems.
New types of radio communication systems are exemplary of communication systems that have been made possible as a result of advancements in communication technologies. In a radio communication system, a radio link interconnects a sending station and a receiving station. Communication channels upon which data is communicated between the sending and receiving stations are defined upon the radio link. Because the radio link is utilized to define the communication channels, wire line connections, conventionally required to interconnect the sending and receiving stations is obviated. Increased communication mobility, relative to a conventional wire line system, is thereby provided in a radio communication system.
A cellular communication system is an exemplary type of radio communication system. A cellular communication system is a multi-user communication system permitting communications to be effectuated concurrently pursuant to a plurality of communication sessions with a plurality of mobile stations operable in the communication system.
Various standards have been promulgated relating to various types of cellular communication systems. And, various types of cellular communication systems have been constructed corresponding to such standards. The IS-95/IS-2000 interim standards promulgated by the EIA/TIA, e.g., are exemplary of standards that pertain to cellular communication systems and which utilize CDMA (code-division, multiple-access) communication techniques. In a CDMA communication system, a plurality of concurrently-generated communication signals are generated concurrently upon a common frequency range. Because of the concurrent use of the common frequency range, the power levels, at which each of the signals are generated upon the common frequency range, must be regulated. If a communication signal is sent upon the communication link at too-high of a power level, the communication signal might interfere with other concurrently-transmitted communication signals upon the communication link.
Closed loop power control schemes are incorporated into the IS-95/IS-2000 family of standards. For instance, to effectuate forward-link power control, a fast power control scheme is used. The forward link refers to the portion of the communication link upon which communication signals, originated at network infrastructure of the CDMA system, are communicated to a mobile station. Forward-link channels are defined upon the forward link. In the fast power control scheme, power control bits are generated and transmitted by the network infrastructure upon a forward link channel to a mobile station. The power control bits are used, once received at the mobile station, to control the power levels at which reverse link communication signals are generated by the mobile station. Two-way power control is effectuated in which power control bits are generated at the mobile stations, transmitted to the base station, and used to control the power levels of signals generated on the forward link.
The existing fast power control scheme is effective in its operation to power-control communication signals, such as those conventionally generated pursuant to a circuit-switched communication session. Circuit-switched communications are advantageously used to effectuate real-time communication services. Use of circuit-switched connections, however, are fairly bandwidth-consumptive. Circuit-switched communications are amenable to power-control pursuant to such a power control scheme. Guarantees of QoS (Quality of Service) levels are better assured when the signals are communicated in manners in which their power levels can be controlled.
As, increasingly, non-real-time communication services are being provided in a radio context, shared channels are able to be utilized to communicate communication signals used to implement the non-real-time communication services. Because a shared channel is potentially utilized to effectuate more than one communication session, the bandwidth available upon a communication link is more efficiently utilized.
Conventional fast power control schemes utilized to effectuate power control in an IS-95/IS-2000 communication system are not readily adaptable to effectuate power control upon shared channels. The non-adaptability of the existing fast power control scheme to shared-channel communications is due to the potentially brief duration of transmission of communication signals pursuant to a particular communication session. The amount of time required for settling of the power control loop formed in the existing, fast power control scheme is potentially greater than the duration of transmission of the communication signal.
A better manner of controlling power levels of communication signals sent upon a shared channel defined upon a communication link in a CDMA communication system is, therefore, required.
It is in light of this background information related to power control schemes in a CDMA communication system that the significant improvements of the present invention have evolved.